Atomically
Precise Manufacturing
Questions and Answers

Atomically precise manufacturing — building
at the molecular scale with engineering control — is the
ultimate Grand Challenge of the National Nanotechnology Initiative.
Only a few years ago, this goal sounded like science fiction, but
recent scientific results show it is within our grasp, if we rise
to the challenge. Developing and commercializing this technology
will deliver substantial economic, social, defense, and health
benefits to our country—and society in general. Some frequently
asked questions and answers concerning this revolutionary technology
follow.

What is atomically
precise manufacturing?Atomically precise manufacturing is the ability
to manufacture materials and structures at the atomic or molecular
size scale. This technology integrates the knowledge and low
manufacturing cost of chemistry with the knowledge and flexibility
of engineering. The result is a manufacturing technology that
achieves the low cost of chemical manufacturing, combined with
the engineering mastery that brings us the microchip or suspension
bridges, and the flexibility and design freedom offered by computer
software. This future manufacturing technology will enable us
to make products in a cleaner, cheaper, and faster way than any
technology that exists today.

Is the Zyvex approach to atomically
precise manufacturing “self-assembly” or some other
method?Self-assembly is a powerful process for creating
materials, and a number of research groups are experimenting in the
field. Zyvex will utilize some aspects of self-assembly, but the
core focus of our technical approach is to create engineered structures
by means of parallel, automated assembly of atoms under computer
control. This positionally-controlled chemistry allows us to achieve
the long-range order of molecular-scale building blocks that is vital
to atomically precise manufacturing. On the other hand, self-assembly
is sensitive to slight changes in the building blocks, making those
systems difficult to engineer. It also suffers from a lack of long-range
order. As an example, imagine building a 200-foot brick wall. A pure
self-assembly approach would start by randomly laying twenty bricks
and building up from each brick independently. One would soon find
that the random sections didn’t join with one another, and
the resulting brick wall would be weak and ugly. Zyvex’s ordered
approach to assembly would start by laying a foundation row of bricks,
and building up from there row by row. Long-range order is extremely
important to engineering strong, useful structures.

The late Nobel Laureate Professor
Rick Smalley said that atomic or molecular assembly won’t
work because atom manipulators would be too fat and sticky.
Was he right?Actually we agree with Professor Smalley. However,
if you look carefully at what he has said, it does not apply to
our approach. Smalley believed that complex, floppy molecules cannot
be put together with atomic pick and place techniques. Our target
is not the kinds of molecules that living creatures make, but rather
rigid, crystalline structures comprised of a small number of elements.
Our approach will use parallel arrays of molecular-scale tools
operating with high precision to create extremely valuable devices
and structures with atomic precision.

Doesn’t quantum mechanics
say that since we can’t know where the atoms are, building
with atomic precision would be impossible?Some implications of quantum mechanics are hard
to understand, which leads to certain myths about quantum uncertainty.
The uncertainty of any particle’s position is related to its
momentum (or mass), so while a light electron may have considerable
uncertainty in its position and momentum, an atom is much heavier
and tends to stay put (which also keeps its electrons nearby). If
atoms were as frisky as the “quantum uncertainty” critics
claim, solid objects would continually evaporate before our eyes
(in fact, life could not exist in such a universe).

Is manipulation at the atomic
scale really possible?
Yes. The first clear demonstration of the arrangement of atoms was in
1990 when Don Eigler arranged 35 Xenon atoms to spell out IBM.1 Since
then, many groups have demonstrated the ability to manipulate atoms into
designed structures. Bob Celotta and Joe Stroscio of the National Institute
of Standards and Technology (NIST) have gone so far as to make the Autonomous
Atom Assembler that can create designed arrangements of atoms in a completely
automated fashion.2 Eigler’s team has
recently created molecular logic structures (see Figure 1 at left).

The IBM and NIST work just
moves atoms around on a surface; however, you are talking
about assembling atoms where chemical bonds are broken
and made. Is that possible?
As a matter of fact, yes. Wilson Ho3 at UC
Irvine, and Saw Hla4 at Ohio University have
manipulated atoms and molecules to make and break chemical bonds (see
Figures 2 thru 4). Figure 3 shows a clear demonstration of what we call
mechanochemistry — where we can move atoms and molecules together
to deliberately make and break chemical bonds.

Eigler, Ho, and Hla are manipulating
atoms and molecules on surfaces. But you are talking
about adding atoms to crystalline structures with atomic
precision. Has that even been done?
Yes, it has. Joe Lyding5 at the University
of Illinois Urbana-Champaign has shown that he can remove hydrogen atoms
adsorbed on atomically flat silicon surfaces. We refer to this as “atomic
precision depassivation.” Michelle Simmons6 at
the University of New South Wales has used this technique to place a
single phosphorous atom at an exact location in a silicon lattice to
form a “Qubit” (the fundamental computing element in quantum
computation). Lyding7 has recently shown
that he can control the growth of single layers of atoms with his depassivation
technique to make three-dimensional structures of crystalline silicon.

Won’t
thermal vibrations keep you from building with atomic
precision? Haven’t you ever heard of “Brownian
motion?”
It is well known that atoms are in a state of constant motion due to
thermal noise. In liquids, small particles are jostled around by the
liquid molecules; an effect called “Brownian motion.” The “thermal
noise” critics claim it isn’t possible to build with atomic
precision due to this effect. However, careful analysis shows that stiff
structures can hold their position with high accuracy even in the presence
of thermal noise. This is proven by thousands of researchers worldwide
making atomic resolution pictures of atomic structures, and doing the
atomically precise manipulations described earlier. If we choose to make
our positioning devices with less stiffness, we can cool the environment,
which reduces thermal vibration to inconsequential levels. This is not
a problem that will stop our progress.

Let’s assume
that you can produce atomically precise three-dimensional
structures with this technique. Is that just a laboratory
curiosity? Is there any near-term return on investment
in this technology?
The most valuable structures that could be made with this technique would
be tools to enable modestly parallel initially, and then massively parallel
systems to produce atomically precise structures more cost effectively.
But there are many highly valuable very small structures that could be
made with a tool that could only assemble things one atom at a time.
One entire class of structures is designed to interact with specific
molecules. One example of this is a nanopore that would have the ability
to read DNA at up to one million bases per second.8,9 Atomically
precise tips for atomic force and scanning tunneling microscopes would
have a huge impact on metrology for the semiconductor industry and for
science in general. Earlier in this white paper, we mentioned qubit for
quantum computing.6 It takes just a handful
of qubits to do quantum encryption. There are many other highly valuable
products that one could create with early stage atomically precise manufacturing
tools.

What about the possibility
of creating runaway nanobots that destroy all life?
Science fiction writers love to use a little pseudo-science to tell a good
story, but we shouldn’t confuse pseudo-science with reality. We intend
to build machines that help us manufacture things with atomic precision. This
is grounded in reality, as evidenced in the research we mentioned earlier.
Building self-aware machines that reproduce in the wild is science fiction,
and likely to remain that way for many decades, even at the macro scale. Nobody
knows how to do this sort of thing even with supercomputers, computerized machine
shops, and unlimited electric power, so worrying about doing it in specks too
small to see, powered by fuel cells we don’t even know how to make, reproducing
themselves by some unknown technology, and programmed by genius programmers
that haven’t even built a robot as smart as a worm, seems a waste of
worry.